Papers alleging Brown broke the law by not declaring free hotel rooms were filed at the Auckland District Court last week.

McCready's private prosecution accuses the second-term mayor of breaking the law by not declaring five free room upgrades from SkyCity for himself and his wife between November 2010 and November 2013.

The upgrades were thought to be worth about $4500, McCready said.

McCready said that Brown's acceptance of the gifts led to "favourable consideration" towards SkyCity and he would prosecute the mayor under section 105(1) of the Crimes Act - corruption and bribery of an official.

He was expected to appeal to the Attorney General to allow the case against Brown to proceed.

Earlier this week, McCready backed down on an announcement he would file papers against Brown's wife, Shan Inglis.

McCready has a record of successfully bringing private prosecutions against public figures, including a case against MP Trevor Mallard for fighting in public, as well as charges against ACT leader John Banks for knowingly filing a false electoral return, which have now been taken over by the solicitor-general.

McCready said he was certain the prosecution against Brown would go "a long way down the track".

Brown would be notified of the filing and would have the opportunity to make his own submissions against the allegations.

After Brown's re-election last year, and in the wake of revelations about his affair with council junior Bevan Chuang, auditors found he accepted hotel freebies valued at more than $39,000 over a two-year period.